1. Field of the Invention
The present invention relates to a contactless electric switch, particularly a switch having a magnetic reset function.
2. Description of the Related Art
What is known are electronic push-buttons or switches by which two contact zones are connected via a short-circuit piece. To achieve a safe switching process and give the operator a haptic feedback, such switches are often designed with a so-called click function. This can be realized, for example, by using a bent membrane that allows for a sudden deflection when a sufficient amount of pressure is applied to the button of the switch, with the deflection being reversible when the button is released. Such switches can be executed, for example, as a membrane keyboard having a single or multiple buttons. Such a keyboard is known from EP 0 841 674 B1.
Further it is known to provide switches with a mechanical spring system in order to facilitate resetting of the pressed button. Here, too, a mechanical contacting detects when the button is being pressed.
For so-called non-contact switches, in which the actuation of their button is detected by means of reed contacts, it is known to dispense with any mechanical contacting. In this case, the field of a permanent magnet causes the contact zones that are made of a magnetic material to touch each other and thus to establish an electrical contact. This means that a contactless actuation occurs, which, however, still involves establishing a mechanical, electrical contact.
A switch that is of a completely non-contact-type is known from DE 102 41 642 A1. Its button is made of a permanent magnet material and, in a resting position, magnetically adheres to an adhesive plate. If pressure is applied to the button, the adhesive plate can be detached and moved through an area monitored by the Hall sensors which are arranged laterally next to the button. In order to accommodate these Hall sensors, the switch is designed so as to have a great width.
The object of the present invention is to provide a compact switch that is designed in a completely non-contact way and in particular has a click-function as well as a good magnetic shielding, so that several such switches can be arranged next to each other while at the same time ensuring trouble-free operation.